Combined safety guard and dust collector



March 7, 1950 M. F. HARRISON COMBINED SAFETY GUARD AND DUST COLLECTOR Filed Dec. 12, 1945 Patented Mar. 7, 1 950 FZFIIICE izneassz l CQMBINEDQSAEETY GUARD: ANDDU-ST IQQLLECTDR Millaid 'FJHarrison, Oakland; Calif.

.Application December 12, 1945,, Serial No.;634 593 Z'ECIaimS. 1

Thisv invention, av combined safety guard arid dust. collector provides in a ,single unit a guard for cutting wheels and acofllectori'for the cuttings. It keeps theair. around. the .operator'j'free of "dust and cuttings, thereby. whileprovidingvtheprotectionv against injury, provided ,by' the conventional guard, it additionally provides protection ofpthe health of ,the operator by eliminating the dust before it can reach the surrounding air, and it can, when .desired, additxmally be arranged .to keep the work, clean "as the operation progresses.

The invention is. equally, suitable for saws .of eitherthe toothed metal typ the: embedded type, or the abrasive type such..asjCarborundum and allied materials, and likewise for idly-grinding wheels.

When plastics andpther syn'thetic products are sawed .orotherwise out toiformorisize, various typeswof abrasive wheels are used; i011 performing the cutting, and .thesewhefels, operating at, high speed, carryconsiderable of the :dustffar enou h around the, wheel to cast "it idirec t1y toward" the operator, andinsome casesflitheairbecomes heavily loaded with dust tobesbrea'thedjby'lthe operator. .Thissdustis. detrimental to. the health of the operator and others within itsrange, and though dustv collectors are known-which are SuDPose'd to eliminate. this Ldust, their, efiectiveness'jis considerab-lybelow the level desired.

This invention,.depending .upon Itheftype of equipment with which .itsis. ,used,. w1ill in, 'a1l. cases prevent any dust fromlbein .cast toward ..;the operator,-.-and whereinstallation permits, it can be arranged to collect all dust formed by the cutting wheel andjdispose'of -it;;in-a:manner in which it can. no further contaminate the air, and while doing so, it can be arrange'd-tokeep thegwork' free of the dust or cuttings.

The objects and advantages .oiithe invention are as follows:

First, to provide a c0mbined.;safety guardiand dust collector for high-speed cutting wheels.

Second, to provide a dust-collector whichwill effectively catch and .collect hall {dust ;;cast ;;off toward 1 the operator by .a .;.high:speed :cuttin wheel.

Third, to provide a dust collector WithuWhich all dust cast by the cutting-.whee1.;;can be caught and collected.

.Fourth, to provide a dust collector as.,.,o.utlined which can .be arranged to" keep the work clean while simultaneously catching and collecting the dust.

Fifth, to provide a dust collector as outlined "2 which simultaneouslyfunctionsas-a'safetib ard for the cutting wheel.

In ,describing the invention reference will :be made to the accom nying drawings injWhiCh':

1Figs l is ,a vertical section throu h the invention, showing both,the dust catching and dust collecting moans arrangedfor catching andlcollecting only the dust which would becast'toward the operator.

Fi ais atopplan vi w o 'Fiell.

"Fig.1; 31s a ,vertical' transverse. section "through the invention taken on lines-=3 of F igrz but, with llhejsuction connection modified for ,r emote location o th du t olle or- Fig. 4 diagrammatically; illustrates a complete unit oh uardmg the w eeLcat hinan c ll me all .r u tpan'd k e n he .w r n a t cutting progresses.

"The invention consists -of' t h e 'saf ety guardifl for guarding thesaw or abrasive wheel;l l, in,connection, with jdustrcatching elements, a j dust collector, a. source of subatmospheriq pressure and pressure above. atmospheric.

1 The dust catchers consist of twp types, onefor catching peripherally-.castdust, and the otherjor catching dust cast from "thesidepf he wheel. The peripheral catchers may be in the term of louvres, thoseshownbeillsa modified'for of louvrev which, as shown yconsi'st of curved blades 12,113, liland' l5 theapproachiends ifi of which flare inwardly toward the saw or grinding whejel leavin abroad, sap fi'l'iior, catc ine h ca f particles, and with the. series o bla es'f qrmih a continuous passage 18 with. the guard :wall 9 functioningas the. opposite wa11". 0 he as a iiTheg-passagei 1.8 terminates in ,a retu n "ben fl at .ithe'lower :forwarjd end. of -t yeua which returnbend isjformedibetweenthebulboustenninai end; not theeuard wa l!!! and the te mina louvreiZ which curves about. this lbous end 2 lyand exterids,about arid over the't op ofthmwaill 19 to form a, suction passagefiz, the passageflZ terminatin in. aconnec ioni 2.3 for a suctionconduit.

The. side-.dus ..ca cher con ist each f alihor likev .member; 24 which'us open. at 25 to. receive the,. dust, castoif fromlftheisidepfl th .WheBLfilDd oneofthe es-catchers islpr v dedliorn ach. ide-p theavheei; thou h n l imitedito one-since.in.c r taincases it xmight be desirable .touse two)cit-more in:.-seri s. ;.'I h es sidedus catch rsvtermieatain restricted passaee lop hin into.theesuotioni a sageszz zthrough'. the. mall: :lz9tasuindicated atiflao.

A suitable clean-out opening is provided at the return bend and this opening is provided with a suitable self-sealing cover 21 which is hinged at 28 and provided with a suitable lock or latch 29.

The dust collecting means consists of an airtight receiver 30 which is partly filled with liquid such as water 3| and a suction conduit 32 which extends substantially to the bottom 33 of the receiver and terminates in an air-dispersing shoe 34 which is provided with a multiplicity of tiny passages 35, the upper end of the conduit being connected to the connection 23 or 36, the conduit being formed integral with or sealed through the cover 3'! of the receiver.

A suction outlet 33 is removably secured in the cover 31 and is provided with a bubble or foam breaker such as a screen 39 and is connected to a vacuum pump 40 through a conduit 4|, the discharge 42 of this pump being available for blowing the dust or cuttings off of the work 43 as through a nozzle 44.

As diagrammatically illustrated in Fig. 4, the vacuum pump 40 draws air through the suction line 4|, thence through the liquid 3| in the receiver and suction line 32, passage 22 and thence through the passages 25, 45, 46, 41 and 48, all of which passages have equal cross-sectional areas, and the total of which areas is equal to the area of the passage 22, to maintain uniform velocity of the air in all parts of the system, so as not to favor settling out of any dust.

As the wheel I rotates at high speed, it carries particles around which are cast off as indicated at 49 and these particles are cast into the gaps l1, and at the same time the increasing suction draws the particles through the passages 25 and 45 to 48 and thence through the passage 22 and conduit 32 to the bottom of the body of liquid 3| where it is dispersed into the liquid through the passages 35, bubbling up through the liquid to the space above the liquid where the velocity is very greatly reduced, the solids remaining in the liquid where they settle to the bottom and where the resultant sludge can be drawn off through the passage closed by the plug 59, at will, the air above the liquid then being drawn up through the screen 39 thence through the conduit 4| to the intake of the compressor 40, and discharged through the conduit 52 through a suitable nozzle 44 over any desired area, such as over the work 43.

Where the complete assembly including blower is used, the guard and collector should extend about the back of the wheel as far as possible, as indicated in Fig. 4, to catch the dust and particles blown by the nozzle 44, the guard having a lip 53 into which the dust is blown.

It will be noted that the vacuum pump pumps only clean air, unlike those which operate in conjunction with a dry separator such as the conventional cyclone type, or those which discharge directly to the outside of a building, therefore the pump is not subjected to any abrasive action. Obviously, a conventional suction fan can be substituted for the vacuum pump shown and may under certain circumstances prove more desirable.

I claim:

1. In a machine having a cutting wheel; a safety guard having a suction passage, and a plurality of dust intercepting members within said guard, and a source of sub-atmospheric pressure for said suction passage; said dust intercepting members comprising a series of louvre type concave members mounted within said guard and having the approach ends in slightly retracted relation to a tangent extending from the rim of the wheel and forming wide gaps therebetween and each terminating at the other end in slightly spaced relation to the back wall of the next member and intermediate its length to form a restricted passage, and with the curved walls and the gaps formed therebetween intercepting and directing dust to said restricted passages, and an air passage having one wall formed by said members and the other walls formed by the walls of said guard, and with said air passage in communication with said suction passage; and side dust catchers mounted in slightly spaced relation to the respective sides of the wheel for catching dust particles thrown off from the side faces of the wheel and each terminating in a restricted passage in communication with said air passage and having a dust intercepting opening extending from a point intermediate the diameter to a point beyond the periphery of the wheel; the area of said suction passage being substantially equal to the combined areas of all of said restricted passages, and said air passage at any point having an area substantially equal to the combined areas of the restricted passages entering up to that point for uniform suction through all of the restricted passages and for minimization of dust gathering and settling in said air and suction passages.

2. In a safety guard for a grinding wheel or the like; a series of concave louvre-type dust interceptors mounted within said guard and each terminating at its inner end in slightly spaced relation to the back wall of the next interceptor and intermediate the length thereof and forming dust-intercepting gaps terminating in restricted passages between the inner terminal ends and the back of the respective interceptors, and a suction passage formed by the inner portions of the back walls of the interceptors and the side and peripheral walls of the guard, and side dust interceptors mounted on the inside of the side walls of said guard and terminating each in a restricted passage opening into said suction passage forwardly of the last of said dust intercepting gaps and having an opening extending from a point intermediate the radius of the grinding wheel to a point beyond the periphery thereof, and with the area of said suction passage at any point being substantially equal to the combined areas of the restricted passages entering up to that point for uniform suction through all of the restricted passages and to prevent accumulation of dust throughout the length of the suction passage.

MILLARD F. HARRISON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 790,943 Weber May 30, 1905 807,530 Yuerhs Dec. 19, 1905 956,762 Furrow May 3, 1910 1,174,659 Bilicki Mar. 7, 1916 1,483,966 Collins Feb. 19, 1924 1,722,853 Morris July 30, 1929 1,912,660 Sequi June 6, 1933 FOREIGN PATENTS Number Country Date 564,675 France Oct. 27, 1923 13,028 Sweden Apr. 12, 1901 

